Industrial production devices frequently comprise robots or machines that are supplied automatically with the material to be processed via a conveyor. Such robots or machines regularly constitute a danger area that is to be monitored with the aid of safety devices. In this case, it is usually necessary for the safety device to be capable of distinguishing the material inflow to the robot or to the machine from persons whose approach to the robot or the machine is not permitted.
There are many solutions in the prior art where reference objects and reference scenes are stored and it is possible during the operation to establish any difference of a current scene from a reference. Some solutions store reference objects whose approach to a danger area is permitted. By contrast, others store the reference objects or scenes that can lead to a dangerous situation and consequently require a specific reaction of the machine or the robot.
German Laid Open Patent Application No. 44 11 448 A1 discloses a three-dimensional measuring device with the aid of which it is possible to detect a contour function of an object and compare it with a stored reference contour. A prescribed reaction of the system can be instituted as a function of how the measured contour matches or does not match a stored contour.
The determination of a contour and its matching with a reference contour can never be carried out completely, since every new object requires detection of a reference contour in a learning process.